JL Audio RBC-1 Owner's Manual page 8

aPPendix d: troublesHooting
"How do i properly set the input sensitivity on my amplifier"
Please refer to Appendix A (page 12) to set the input sensitivity for
"my amplifier doesn't turn on"
Check the fuse, not just visually, but with a continuity meter. It is
Check the integrity of the connections made to each of the
Check to make sure there is +12V at the "Remote" connection of the
amplifier. In some cases, the turn-on lead from the source unit
is insufficient to turn on multiple devices and the use of a relay
is required. To test for this problem, jump the "+12VDC" wire
to the "Remote" terminal to see if the amplifier turns on. If this
does not work, proceed to the next step.
"i get a distorted / attenuated sound coming out of the speaker(s)"
Check the speaker wires for a possible short, either between the
Check the nominal load impedance to verify that of the amplifier is
Check the input signal and input signal cables to make sure signal
"my amplifier's output fluctuates when i tap on it or hit a bump"
Check the connections to the amplifier. Make sure that the
Check the input connectors to ensure that they all are making good
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maximum, low-distortion output.
possible for a fuse to have poor internal connections that
cannot be found by visual inspection. It is best to take the
fuse out of the holder for testing. If no problem is found with
the fuse, inspect the fuse-holder.
"+12VDC", "Ground", and "Remote" terminals. Ensure
that no wire insulation is pinched by the terminal set screw
and that each connection is tight.
positive and negative leads or between either speaker lead
and the vehicle's chassis ground. If a short is present, you
will experience distorted and/or attenuated output. The
"Protect" light will illuminate in this situation. It may be
helpful to disconnect the speaker wires from the amplifier
and use a different set of wires connected to a test speaker.
driving a load equal to or greater than 2 ohms.
is present at the "Amplifier Inputs" and the cables are not
pinched or loose. It may be helpful to try a different set of
cables and/or a different signal source to be sure.
insulation for all wires has been stripped back far enough to
allow a good contact area inside the terminal block.
contact with the input jacks on the amplifier.
JL AUDIO G-MAX
"my amplifier shuts off once in a while, usually at higher volumes"
Check your voltage source and grounding point. The power supply
"my amplifier turns on, but there is no output"
Check the input signal using an AC voltmeter to measure the
Check the output of the amplifier. Using the procedure explained in
Check to ensure that the speaker wires are making a good
JL AUDIO G-MAX
of the G-MAX will operate with charging system voltages
down to 10V. Shutdown problems at higher volume levels
can occur when the charging system voltage drops below
10V. These dips can be of very short duration making them
extremely difficult to detect with a common DC voltmeter.
To ensure proper voltage, inspect all wiring and termination
points. It may also be necessary to upgrade the ground
wire connecting the battery to the vehicle's chassis and the
power wire connecting the alternator to the battery. Many
vehicles employ small (10 AWG - 6 AWG) wire to ground the
battery to the vehicle's chassis and to connect the alternator to
the battery. To prevent voltage drops, these wires should be
upgraded to 4 AWG when installing amplifier systems with
main fuse ratings above 60A. Grounding problems are the
leading cause of misdiagnosed amplifier "failures."
voltage from the source unit while an appropriate test tone is
played through the source unit (disconnect the input cables
from the amplifier prior to this test). The frequency used
should be in the range that is to be amplified by the amplifier
(example: 50 Hz for a sub bass application or 1 kHz for a full
range / high-pass application). A steady, sufficient voltage
(between 0.2 and 8.0-volts) should be present at the output of
the signal cables.
the previous check item (after plugging the input cables back
into the amplifier) test for output at the speaker outputs of
the amplifier. Unless you enjoy test tones at high levels, it is
a good idea to remove the speaker wires from the amplifier
while doing this. Turn the volume up approximately half
way. 5V or more should be measured at the speaker outputs.
This output level can vary greatly between amplifiers but it
should not be in the millivolt range with the source unit at
half volume. If you are reading sufficient voltage, check your
speaker connections as explained below.
connection with the metal inside the terminal block. The
speaker wire connectors are designed to accept up to 8 AWG
wire. Make sure to strip the wire to allow for a sufficient
connection with the metal inside the terminal block.
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